So swarming is the multiplication of bee colonies by emigration of a part of the hive population.

Bees swarm, gathering around a branch or in a scrub and waiting to find a new home.
They are collected by a bee keeper and put into a new home.

A swarm is the natural reproduction. The new queen makes a fecundation flight. She mounts very high and high in the sky she mates with several drones. After these flights she is able to lay fecundated eggs and non fecundated eggs. Workers hatch from fecundated eggs and drones hatch from
non fecundated eggs. This is the only function of the drones: the fecundation of new queens.
It is unnecessary to explain what a wonderful experience it is to see a swarm in action.
Thousands of bees flying around at the same time. It is not dangerous at all to take a close look because the bees are too busy to bother about the spectators. As you know the bees are filled with honey and for that reason they can hardly put out their stings.